Feeding behavior of lactating brown lemur females (Eulemur fulvus) in Mayotte: influence of infant age and plant phenology.

Altmann [Baboon Mothers and Infants, University of Chicago Press, 1980] and Dunbar and Dunbar [Animal Behavior 36:970-980, 1988] provided a model that predicts the amount of time spent feeding by lactating baboon females, as related to infant age. Dunbar's model further suggests that food quality affects the amount of time that females devote to feeding activity, and is predictable from rainfall and temperature data. In this study the model was tested with data recorded from births of the Mayotte brown lemur from four maternal dyads (Eulemur fulvus). This study also examines the correlation between female activity budget, quantities of fresh plant matter ingested, and suckling duration using data collected from focal animal samples on the mother-infant dyads. The relationships among rainfall, food supply, and food quality were also tested. It appears that female brown lemurs do not devote more time to feeding during the infant growth period. The data show that female brown lemurs increased their food intake during the early-lactating period when the frequency of suckling is the highest, and before infants begin to eat substantial amounts of solid foods. Thus, the frequency of feeding reflects the cost of lactation better than suckling duration. Furthermore, females did not appear to select foods according to their availability or rainfall levels. I hypothesize that the lack of convergence between lemur data and baboon observations is due to differences between their respective environments and their feeding ecology. These data also indicate that the most significant lactating cost for the brown lemur occurs during the early lactation period.